Added Workflow.get_data_file_name() which returns the full path to a given

data file, or None if the file does not exist. This is tested in the test
workflow.

fluents/workflow.py

@@ -63,6 +63,19 @@ class Workflow:
         self.stages_by_id = {}
         self.app = app
 
+    def get_data_file_name(self, filename):
+        """Checks if a file with the given name exists in the data directory.
+        Returns the file name if the file exists in the data directory, which
+        is defined as datadir/workflowname. If the file does not exist, or the
+        workflow does not have an identificator, this method returns None."""
+        print os.path.join(self.app.options.datadir, self.ident, filename)
+        if self.ident == None:
+            return None
+        fn = os.path.join(self.app.options.datadir, self.ident, filename)
+        if os.path.isfile(fn):
+            return fn
+        return None
+
     def add_stage(self, stage):
         self.stages.append(stage)
         self.stages_by_id[stage.id] = stage

workflows/test_workflow.py

@@ -17,6 +17,7 @@ class TestWorkflow (workflow.Workflow):
 
         load = workflow.Stage('load', 'Load Data')
         load.add_function(CelFileImportFunction())
+        load.add_function(DataLoadTestFunction(self))
         load.add_function(TestDataFunction())
         load.add_function(DatasetLoadFunction())
         load.add_function(SelectFunction())
@@ -257,6 +258,22 @@ class CelFileImportFunction(workflow.Function):
             chooser.destroy()
 
 
+class DataLoadTestFunction(workflow.Function):
+    def __init__(self, wf):
+        workflow.Function.__init__(self, 'datadirload', 'Load from datadir')
+        self._wf = wf
+    
+    def run(self):
+        print self._wf.get_data_file_name('smoker-x.ftsv')
+        fn = self._wf.get_data_file_name('smoker-x.ftsv')
+        if fn:
+            fd = open(fn)
+            ds = dataset.read_ftsv(fd)
+            return [ds]
+        else:
+            print "Cannot find file %s" % fn
+            return []
+
 class PCAFunction(workflow.Function):
     """Generic PCA function."""
     def __init__(self, wf):